For millions of years plants have been cleaning the air, taking in airborne toxins through their stomata, breaking some of these toxins down and transporting the rest down to their roots where they excrete them, whereupon microbes that congregate close by a plant's root system, digest them and transform them into a food source for higher forms of life. For thousands of years humans have taken plants into their homes and unwittingly purified indoor air. Yet it has only been since the early nineteen eighties that plants have purposely been grown in an artificial soil, where air movement mechanisms pull poor indoor quality air directly down into that soil, and where air purifying microbes within that soil break down the impurities contained within indoor air and more efficiently, thereby purify a building's air supply. Such science, much of it developed by NASA, has eliminated the need for plants to act as a transport mechanism of impure air and as a result a single plant can now do what hundreds of plants had done previously with regard to indoor air purification. Consequently, there is now sufficient room within a building or within an enclosure attached to a building, to purify almost all of a building's indoor air supply without the need of anything beyond the smallest amounts of outdoor ventilation.
Presently ventilation is the main way to deal with indoor air quality, and since such ventilation often results in additional heating and cooling expense, not to mention higher equipment costs, the use of plant air purification is a welcome alternative which lowers operating costs for a habitable structure and make its indoor environment healthier.
However, up to this time, the use of plant air purification has been limited, often because plant air purification takes up more habitable space than building owners or managers are willing to give up and because ASHRAE, which governs the requirements for heating and ventilation of buildings within the United States, has been concerned with what would happen if plant air purifying apparatus were to malfunction. But if space which is not considered habitable were used to install house plant air purifiers, and if there were a means for a building to automatically return to outdoor ventilation if the plant air purification apparatus were to fail, then such a new technology might be more widely accepted. The invention disclosed here, overcomes these two major concerns.
ASHRAE 62 states that a ventilation system must provide minimum quantities of outdoor air (OA) per building square foot or, alternatively, achieve certain minimum standards for indoor air quality (IAQ). By neutralizing bacteria, VOCs, and smoke particulates, alternative air treatment can enable an HVAC system to achieve sufficient IAQ while requiring lower outdoor air volumes, thus reducing the air conditioning capacity to condition outside make-up air, simultaneously reducing supply, return and exhaust fan energy consumption, as well as the energy needed to condition the OA.
Recent studies at Syracuse University's Center of Excellence, as stated in BEESL-RO1-09-09-COE-TAD-Final Report, sponsored both by the Environmental Protection Agency and the New York State Energy Research and Development Authority, showed that just 8 low level light-requiring plants, grown within a plant air purifier of just 12 square feet, hooked up to a building's HVAC system were able to purify the air within a 1900 square foot space and lower ventilation levels to 5%, thus saving 26% on heating costs. In this study the filter bed size of a plant air purifier used only 0.006315 (0.6%) of the floor space of the area whose air it cleaned. That would amount to the need for only 631.5 square feet of filter bed space for a building with a 100,000 square feet of habitable space. This can be very easily accomplished where new construction is envisioned, but is not always easily achieved when an already existing building had to be retrofitted and its space reallocated. This invention, however, has overcome that problem, by housing a decent sized plant air purifier within an enclosure/housing known as a Plant Air Purification Enclosure (PAPE), and by placing it in unconditioned space within the building which is little used and of marginal value, space which is often unfinished and which does not meet code requirements for habitable space. A PAPE can even be located outside a building, or installed in a mobile unit which can be driven up to the building and simply hooked into its HVAC system. PAPEs can even be utilized to purify incoming outside air (OA) as well, even in a smog laden environments.
To do so, however, certain requirements must be met:                The enclosure must have suitable light for so many hours each day.        Air and water, supplied to the enclosure, should stay within a temperature range of 60 to 85 degrees        Fahrenheit in the most ideal circumstances.        Water used in the plant air purifier in the enclosure should be pure—free of chlorine, fluorides and high levels of acidity.        Humidity within the enclosure should be kept within a certain range which the plants within the enclosure prefer, or adequate water must be supplied to the plants therein so that they may provide humidity of their own through transpiration.        An additional blower or air movement mechanism should be installed to make up for pressure loss which will certainly occur were a PAPE to be attached to an already existing HVAC system of an existing building.        Other air purification methods, such as the passing of incoming air through ultraviolet light, should also be available.        Adequate sink and counter space for easy maintenance of the filter beds and the plants therein should be part of the layout.        An easy means of conveyance of plants and trays which contain the filter beds of the plant air purifiers must be available since the trays themselves might be quite heavy and bulky.        The enclosure should be well insulated, neither gaining nor losing great quantities of thermal energy at any time during the year when ambient air temperature outside the enclosure either exceeds or is less than the ideal temperature range suitable for the plants within to live.        The enclosure should have emergency backup for heat, electricity, water and light.        An emergency source of outside air to the enclosure should be available for intake or exhaust in emergency situations.        A mechanism should be installed so that were a malfunction to occur, management would be notified immediately.        Were a malfunction to persist, or if air from the conditioned space failed to pass through the enclosure for any length of time, then the outside air damper to the structure itself would have to reset automatically to provide more outside air for ventilation purposes since the plant air purification enclosure was no longer operable.        
Such needs have all been dealt with by the invention to be disclosed herein, while also allowing for easy installation of a PAPE at minimum cost.
Prior art does not appear to disclose or suggest a plant air purification enclosure, providing the needed infrastructure to make use of plant air purification on a wide scale. However there do exist other types of specialized, environmentally controlled utilitarian enclosures such as clean rooms, deep freezers, green houses, etc. But none of these could be effectively utilized as a plant air purifier enclosure, especially since the enclosure is so tied to the workings of the conditioned space whose air it is purifying.
Some documents defining the general state of the art include the following:
U.S. Pat. No. 5,833,293 appears to disclose a portable greenhouse on wheels where the frame of the greenhouse is welded to a conventional flatbed car trailer. However this invention relies on natural sunlight while the present invention has the ability to be fully enclosed with no sunlight entering whatsoever, and lacks many of the other desirable features of a PAPE as disclosed herein.
U.S. Pat. No. 4,961,763 discloses only a single tier of plants. The microbes necessary for purification needed to be replaced from time because the plant air purifier needed to be in close proximity to the roots of certain plants. By placing plants in a plurality of tiers, there is no need for replacement of the microbes.
U.S. Pat. No. 3,717,953 appears to disclose the growing of mushrooms in specific areas in wheeled trays stacked one on top of another. Growing of plants is not the same as using plants for air purification. There are additional factors that have to be dealt with for a stacked tray arrangement to work with plant air purification. All trays must be within a container that allows the impure air to flow through the filter beds and not escape around the sides. Then the purified air must be ducted away to the desired location without it being lost during transit, or without the purified air's temperature changing dramatically. Water must be supplied to those trays in the stacked arrangement and supplied quite often, usually more than once per hour. Moisture sensors must be set into the trays to automatically turn on the irrigation when moisture levels drop below a certain point. The irrigation mechanisms must be capable of being easily detached if a tray is taken from the tiered arrangement. An airtight seal must be had between the lowest tier of plant trays and the plenum which ducts the air out. Plus lighting requirements of the plants within the tiered structure will be quite a bit greater than for mushrooms. Lighting must be set to a timer and the bulbs protected from moisture during the irrigation process when water spray might come from both above and below.
U.S. Pat. No. 3,991,514 appears to disclose a method of growing plants in a tiered arrangement where the lights are protected from moisture. Again this patent falls well short of a multi tiered plant air purifier such as shown in this invention.
U.S. Pat. No. 6,663,769 appears to deal with having a multi source of supply of pure water for plants. This disclosure utilizes rainwater and tap water to supply water to a structure and includes the watering of plants. However, while it buffers the rain water with CaCo3 of which limestone is a source, it does not treat the tap water by allowing chlorine to leave it prior to entry into an area where plants grow as in this invention. Further, it does not acclimate the water's temperature to that which the plants desire by placing it in an acclimation tank. It does not use humidifiers or air conditions as a source of water supply, nor well water. It does not provide all the information necessary to make the system applicable to a plant air purifier or take care of additional sources of supply of pure water for the plants, and microbes within the filter bed.
Lastly, as relates to a wet scrubber used to clean outside air entering a building, no information appears to be available. Wet scrubbers have been used for industrial situations or to remove certain gases found in a furnace but none have been patented to this inventor's knowledge for indoor application within a building where human occupancy is the primary purpose of the space where the air will be utilized.
It is commonplace these days to start with an existing HVAC and ducting system, and add such things as humidifiers or dehumidifiers, electromechanical air filters and purifiers, etc., because there devices can be made modular and readily retrofitted into a preexisting system, or included from the outset in the installation of a new system. While the basic science of plant air purification is well known, as exemplified for example by National Aeronautics and Space Administration, Spinoff 2007, Plants Clean Air and Water for Indoor Environments, accessible at http://www.sti.nasa.gov/tto/Spinoff2007/PDF/basic_version—07.pdf, pages 60-61, there are at present significant barriers to entry against using plant air on a widespread commercial scale because the technology to systematically integrate plant air purifiers into preexisting or even new buildings and HVAC systems has not been properly and systematically developed. This deficit needs to be addressed.
Fundamentally, the object of this invention is to specify devices, systems and methods to house/enclose plant purifiers in such a way that they can readily be deployed on a wide scale. The sorts of plant air purifier housing devices, systems and methods to be disclosed herein—which can be thought of as the supporting infrastructure which will enable the practical and effective use of plant air purifiers to take root on a wide commercial scale—are what are referred to herein by the shorthand PAPE. The widespread deployment of plant air purification systems, using the disclosures developed herein, will yield significant benefits in terms not only of cleaner, more healthful indoor environments, but also, more efficient energy usage.